SHARE-BASED COMPENSATION EXPENSE

3 Months Ended

Mar. 31, 2017

Share Based Compensation [Abstract]

Share-Based Compensation Expense

6. SHARE-BASED COMPENSATION EXPENSE

The following table summarizes the Company’s stock option activity during the three months ended March 31, 2017:  

	Number of Shares			Weighted-Average Exercise Price Per Share		Weighted-Average Remaining Contractual Life (years)		Aggregate Intrinsic Value
Outstanding, January 1, 2017		577		$	16.04
Granted		0			0.00
Exercised		(93	)		19.47
Forfeited/expired		0			0.00
Outstanding, March 31, 2017		484		$	15.38		4.32	$	19,424
Exercisable, March 31, 2017		253		$	12.69		3.71	$	10,826
Vested and expected to vest at March 31, 2017		481		$	15.37		4.31	$	19,288

The Company recorded compensation expense of $262 and $289 in the accompanying consolidated statements of operations during the three months ended March 31, 2017 and 2016, respectively, for stock option awards. The total intrinsic value of stock options exercised during the three months ended March 31, 2017 was $1,893.  No stock options were exercised during the three months ended March 31, 2016.

The Company has issued restricted stock to employees generally with vesting terms ranging from two to four years. The fair value is equal to the market price of the Company’s common stock on the date of grant. Expense for restricted stock is amortized ratably over the vesting period. The following table summarizes the restricted stock activity for the three months ended March 31, 2017:

	Number of Shares			Weighted-Average Grant-Date Fair Value		Aggregate Intrinsic Value
Nonvested, January 1, 2017		216		$	21.51
Granted		140			35.11
Vested		(103	)		15.28
Forfeited		(1	)		27.43
Nonvested, March 31, 2017		252		$	31.60	$	14,033

Additionally, the Company grants performance-based restricted stock units. The performance-based units have performance conditions and service-based vesting conditions. Each vesting tranche is treated as an individual award and the compensation expense is recognized on a straight-line basis over the requisite service period for each tranche. The requisite service period is a combination of the performance period and the subsequent vesting period based on continued service. The level of achievement of such goals may cause the actual amount of units that ultimately vest to range from 0% to 200% of the original units granted. The Company recognizes expense ratably over the vesting period for performance-based restricted stock units when it is probable that the performance criteria specified will be achieved. The fair value is equal to the market price of the Company’s common stock on the date of grant.  

The following table summarizes the restricted stock unit activity for the three months ended March 31, 2017:  

	Number of Restricted Stock Units			Weighted-Average Grant-Date Fair Value		Aggregate Intrinsic Value
Nonvested, January 1, 2017		281		$	23.18
Granted		73			35.75
Vested		(26	)		21.64
Forfeited		0			0.00
Nonvested, March 31, 2017		328		$	26.10	$	18,191

The Company recorded compensation expense of $2,055 and $1,058 in the accompanying consolidated statements of operations for the three months ended March 31, 2017 and 2016, respectively, in connection with the issuance of the restricted stock and restricted stock units. As of March 31, 2017, the Company expects 247 shares of restricted stock and 323 restricted stock units to vest.

As of March 31, 2017 there was $13,157 of total unrecognized compensation expense related to unvested share-based compensation arrangements, which is expected to be recognized over a weighted-average period of 1.1 years. The total unrecognized compensation expense will be fully charged to expense through the first quarter of 2020.